The present invention relates generally to improving the environmental durability of coated glass panels that are used in displays and similar applications, and more particularly to a coated glass panel that has been treated to remove particles before backfilling the voids left by the particles with an overcoat material.
Glass panels are used in a wide variety of display technology. Displays that can use glass panels include television sets, computer screens, and instrument panels, to name a few. The glass panels are often coated or otherwise treated to improve the performance characteristics or meet a specified requirement of the display. For example, a panel might be slightly etched to reduce reflectivity, or an anti-reflective film or coating might be applied to the front and/or back surface of the glass panel.
Films or coatings might be applied in a variety of ways. One approach applies a self-adhesive sheet of polyethylene terephthalate (“PET”) to a glass panel. The PET sheet may be coated itself, such as with an anti-reflective (“AR”) coating. The AR coating is typically a layer or layers of materials that improve the optical match between the PET and the air. Other techniques deposit a layer or layers of material directly onto the surface of the glass panel.
Some display products generate electro-magnetic interference (“EMI”), and glass panels used in such displays might be treated to reduce the EMI radiated from the panel into the environment, particularly toward a user. In some instances, a fine wire mesh is attached to or imbedded in a glass panel assembly to reduce emissions. The wire mesh is typically grounded through a wire. Such an assembly can be expensive and reduce the clarity or resolution of the display. Another approach has been to deposit a low-emissivity (“lowE”) coating onto the surface of the glass panel. LowE coatings have been developed by, and are available from, a number of suppliers and often contain silver, copper, or gold incorporated into a layer or layers of the coating. LowE coatings typically have better than 45% transmission in the visible spectrum and a sheet resistivity of less than 5 Ohms per square, and in some instances have a sheet resistivity of about 0.5 Ohms per square.
Unfortunately, lowE coatings are often moisture sensitive, and moisture intrusion can induce corrosion in the coating layers. In particular, humidity can infiltrate the low-E coating and cause “blooms” to appear, which degrade the appearance of the panel. Moisture typically infiltrates through a defect in the coated layers. Several techniques address reducing the formation of defects, and other techniques have been developed to seal the defects. One approach is to attach a sheet of PET to the lowE coating with pressure-sensitive adhesive to seal the defects. The relatively thick PET layer protects the lowE coating from environmental moisture. The front surface of the PET sheet is coated to reduce reflections in some instances, typically in a roll coater before the PET sheet is applied to the glass.
However, using such a polymer sheet increases the number of components and assembly steps required for the glass panels. This in turn increases costs and decreases product yield and mechanical durability.
Therefore, a glass panel that can provide EMI shielding, high clarity, and that is resistant to moisture-induced corrosion is desirable.